In the making of jackets for floppy disks, it is important that the jackets have the proper dimensions and shape to fit properly in disk drives of conventional construction. Such disk drives will not accept a floppy disk if the jacket of the floppy disk is not within predetermined tolerance ranges as to warpage, thickness, squareness, and parallelism with reference to the edges of the jacket. Thus, it is mandatory that the jackets be of the proper size and shape and to be able to conform to a desired configuration within tight tolerances. To assure that jackets meet these requirements, a need has existed for an improved apparatus and a method for determining the dimensional characteristic of the jackets of floppy disks so that such jackets can be readily used with conventional disk drives. The present invention satisfies this need as hereinafter described.